This invention relates to a scanner head for an ultrasonic imaging system such as shown in Rutherford U.S. Pat. No. 4,625,557. In such prior patent, there is disclosed an acoustical imaging system which is useful, for example, in imaging the thickness and defects in structures such as pipes or pipelines. Such imaging system uses a scanner head which includes a position encoder which provides distance increments signals as the scanner head is moved over the surface. The encoder is driven by a roller on the scanner head which runs against the surface of the pipe or other object being analyzed. The position encoder drives the ultrasonic transceiver and display circuitry. The scanner head may move in opposite directions on rollers, and being hand held, in any direction.
Unfortunately a major shortcoming of ultrasonic transducers is that the surface of the object being analyzed must have ultrasonic couplant applied to limit the acoustic impedance of air. The amount and nature of the couplant may vary widely depending on many factors such as the shape of the surface, type of surface of the structure being analyzed, the temperature of the structure, or ambient temperature. Moreover, excess temperatures may be deleterious to the scanner head. Excess heat can, for example, cause transducer crystals to expand. This can alter measurements taken and give false readings, and reduce the useful life of the system.
In the system of such prior patent, the scanner head is designed to be at least hand held and to move in any direction forward or backward. The operator moving the scanner head is also usually observing the image created. Thus, the manual application of couplant to the structure being analyzed significantly slows the analytical process. Since the scanner head is designed to move along in real-time, the couplant delivery system should accommodate, for example, a 17 inch per second ultrasonic scanning, all without distracting, limiting, or slowing the operator.